I wanted to start exploring the wealth of data that is contained in Delicious and thought I’d start by building a Python interface to the Delicious-supplied API’s. I found, of course, that someone had already built one. It was a bit out of date — there have been changes in Delicious’ presentation since this library was originally authored — so I made a few adjustments to re-align it with the current service. If you’re interested, you can find the updated version here.
I spent some time today looking at tags. In comparison with formal ontologies, tags are really appealing because there’s no initial hump to get over before you can start using them. (Some have pointed out that even the low barrier to entry posed by tags is too high for many: a large fraction of photos uploaded on Flickr aren’t tagged at all.)
Of course, this simplification comes at a cost. Because there’s no ontology, semantics may emerge but they’re not explicit. So, in general, one user’s precise meaning in attaching a tag may be at odds with the meaning attached by another user. This lack of crispness simply comes with the territory, and introducing ontologies into this arena would solve the problem only by destroying the attraction of tags: their simplicity.
There’s been a lot of discussion about tag clouds, but frankly, other than the amusing visual representations, I don’t see much utility. I wonder, though, whether there’s a more interesting co-occurence statistical analysis that can be done on tags that might reveal useful semantics. It seems like it’d be possible to use Delicious’ API to pull out a bunch of tags to do some analysis.
This post raises an interesting question regarding users’ mental models for tags: is a tag a folder? Or is a tag an annotation? The author posits that Delicious encourages users to think of tags as being the former, while Flickr encourages the latter. He cites a single piece of data from the way his own blog had been tagged by users to suggest that Flickr’s “annotative” model is winning the battle for mindshare.
This is significant because Flickr’s annotative model supports a potential extension for tags that isn’t so well supported by Delicious’ “categorization” model. Namely, I wonder what might happen if we extended the definition of tags so that they are actually user-defined attributes which can have user-defined values. Suppose, for example, that you could tag something as “age: 30″ — would people actually do that, and what kinds of additional expressive power would be unleashed? What kinds of search and aggregation would be enabled?